ErgoPractice News – November 2019
Your Team’s Health Matters:
Blue Light Hazard with LED Lights – Fact or Fiction?
White LED lights have become popular light sources for various lighting applications, including clinical overhead lights and headlights. Dental professionals know that blue light in curing lights is very harmful to the eyes, and thus a protective orange filter is used.1-3 The blue light used in curing lights is the same blue light present in the white LED chips used in most LED headlights sold today. Recently, ANSES (French Agency for Food, Environmental and Occupational Health & Safety) confirmed the toxic effects of blue light, and a recent ADA article reviewed the effects of blue lights.4-5 However, most clinicians may not recognize that bright, cool LED headlights can damage their eyes.
This issue of SurgiTel’s ErgoPractice News is written to inform readers of the eye safety concerns currently associated with the use of bright, cool LED headlights. It has been proven that SurgiTel true color-neutral LED lights offer minimum blue light hazard and the best color accuracy.6 Questionable LED headlights should be compared against a true color-neutral LED light in order to evaluate their safety.
What is LED Light?
White LED lights consist of two spectral bands: blue spectral bands and green/red spectral bands.7 Figure 1 shows the spectral distribution of four light sources. The area where the light helps us see best is under the dotted line. The area where the most dangerous light exists is under the solid black line. The “Cool LED Spectrum” is the most dangerous of all light sources, more so than sunlight and far more than “Warm LED Spectrum.” We wear sunglasses to protect ourselves against too much sun, but it looks as if we should also be wearing sunglasses when using Cool LEDs!
In May 2017, Clinicians Report measured correlated color temperatures (CCT) of various LED light beams.8 Based on these measured CCTs, LED headlights can be classified into several types: warm (2,700 to 3,000K), neutral (3,900 to 4,000), low cool (5,500 to 6,000), medium cool (6,500 to 7,000), and extreme cool (7,500 to 10,000).8
Blue Light Hazard: Why Do Clinicians Use Shields When Using Curing Lights?
Prolonged exposure to bright blue light can damage the retina, causing early-onset, age-related macular degeneration (AMD). AMD is the deterioration of the macula, which is the small central area of the retina that controls visual acuity. The health of the macula is very important for reading, recognizing faces, and performing various visual tasks that require seeing in fine detail. Figure 2 shows an image seen through normal, healthy eyes, and another image seen through eyes with AMD. AMD is the leading cause of vision loss among older people. This may be caused by a prolonged lifetime of exposure to blue light sources. In order to minimize the risk of AMD and to prevent early-onset, we must avoid the use of bright, cool LED lights.
Blue Light Hazard vs. Correlated Color Temperature (CCT)
Cooler LED lights have stronger blue tones. Thus, cooler LED lights are more hazardous to your eyes. There is a strong, linear correlation between blue light hazard and CCT (Figure 3).5 As the CCT increases, blue light hazard risk increases. The CCT of LED headlight beams can be significantly higher than the CCT of LED chips if the beam-forming optics of LED headlights do not use true color beam-forming technology.
The safest LED headlights with the best color accuracy use neutral LED chips (4,000K) and true color optical technology. In May 2017, Clinicians Report measured the CCT of various LED headlights available today.6 The majority of LED headlights used today are extremely cool (6,500K to 10,000K), which can be very harmful to eye health. If you want to prevent AMD, you should avoid the use of these cool LED headlights.
Although some companies claim that their LED headlights meet blue light safety requirements, this is for marketing purposes only. There are no proper government regulatory standards for the safety of clinical LED headlights.
SurgiTel True Color Neutral LED Headlight as the Reference LED Headlight
How can you avoid blue light hazard from cool and extreme cool LED headlights? First, you can check the CCT of the LED chips used for your LED headlights. If the CCT is higher than 6,000K, those LED lights should be avoided. Some manufacturers may claim that their LED headlights are using neutral LED chips, but the CCT of their headlight beams will still be extremely cool if true color beam-forming optics technology is not used.
As an example, let’s compare the beams of two popular brand LED headlights in which both manufacturers claim that they use neutral LED chips. Figure 4 shows the beams of these two popular brand LED headlights. Figure 4a is the beam of SurgiTel’s neutral LED headlight, which is formed with patented true color optical technology, while Figure 4b is the beam of Lumadent’s HL360 LED headlights, which are claimed as “neutral”. The beam of Lumadent’s HL360 headlights seems extremely cool (its CCT may be larger than 7,500K, estimated by comparing with a color chart vs CCT), certainly not neutral. Lumadent claims that the color rendering index (CRI) of this beam is as high as 90, but the CRI of this blue-tinted beam may be significantly lower than 70, increasing the risk of blue light hazard.
It is very difficult to estimate the degree of coolness of LED beams. The best way available is to compare the beam of your current LED headlight with a true color-neutral LED headlight, which has a balanced color spectrum and is safest to eyes. The SurgiTel true color-neutral LED light is an ideal light to use as the reference light. As determined by Clinicians Report, this light has a CCT of 4,000K.6
If you do not have access to a 4,000K light to do this comparison, contact your local SurgiTel Service Representative at www.SurgiTel.com/MyRep, and they will help you determine the difference.
If you wish to avoid the potential loss of vision in your later life, strongly consider making this comparison now!
- Stamatacos, Catherine, DDS; Janet L. Harrison, DDS. “The Possible Ocular Hazards of LED Dental Illumination Applications.” TDA Journal – Continuing Education 93-2 #51 (2013): 25-31. Web. 22 Oct. 2015.
- Price Curing Lab. “The Blue Light Hazard in Medicine and Dentistry.” YouTube. Price Curing Lab, 22 July 2012. Web. 24 Apr. 2015. https://youtu.be/VfCmL4Kz2iw US Department of Energy, Solid-State Lighting Technology Fact Sheet, June 2013
- Chang BJ, Is your LED Headlight Types Safe for Your Eyes? ErgoPractice News Nov, 2018, https://surgitel.com/is-your-led-headlight-type-safe-for-your-eyes/
- OPINION of the French Agency for Food, Environmental and Occupational Health & Safety on the “effects on human health and the environment (fauna and flora) of systems using light-emitting diodes (LEDs)”; ANSES Opinion Request No. 2014-SA-0253; Maisons-Alfort, 5 April 2019
- Fluent, Marie, DDS; Jack Ferracane, PhD; James Mace, DDS; Anjali Shah, MD; Richard Price, DBS, DDS, MS, FDS, RCS (Edin), FRCD (C), PhD. “Shedding Light on A Potential Hazard, Dental Light-Curing Units” JADA 2019: 150(12): 1051-1058
- An independent, non-profit dental education and product testing foundation, Clinicians Report, August 2016. For the full report, go to: www.surgitel.com/CR
- US Department of Energy, Solid-State Lighting Technology Fact Sheet, June 2013
- An independent, non-profit dental education and product testing foundation, Clinicians Report, May 2017. For the full report, go to: www.surgitel.com/CR
- ANSES (French Agency for Food, Environmental and Occupational Health and Safety) confirmed that prolonged exposure to blue light from cool LED headlights can damage the retina, causing early-onset, age-related macular degeneration (AMD).
- SurgiTel can evaluate your current LED headlights against our true color-neutral LED headlights to ensure that your headlights are safe for your eyes.